A YIG-MCT composite substrate for circulators with high shear strength and good dielectric properties was prepared by direct co-firing. The Bi 0.3 Y 2.3 Ca 0.4 Zr 0.4 Fe 4.6 O 12 (B-YIG) ceramic acted as the inner core, and the 0.95MgTiO 3 -0.05CaTiO 3 (95MCT) ceramic acted as the outer ring of the co-fired composite substrate. The influence of co-firing temperatures on the phase composition, microstructure, shear strength and dielectric properties of the as-prepared composite substrate was investigated. Moreover, the transition region of the composite substrate, induced by direct cosintering, was deduced. The results show that the optimal co-firing temperature of the composite substrate is 1280 °C. At the co-firing temperature, the obtained composite substrate shows a high shear strength of 64.20 MPa. New phases, such as MgFe 2 O 4 , Y 2 Ti 2 O 7 , and YFeO 3, form in the transition region because of the interface reaction occurring between B-YIG and 95MCT. The synthesized YIG-MCT composite substrate shows a dielectric constant of 19.7 and a dielectric loss of 5.64 × 10 −4 (9 GHz), demonstrating good dielectric properties. The results indicate that YIG-MCT prepared by co-firing technology is a promising composite substrate for circulator applications.
Haiyi Peng,Chuanqing Zhao,Haishen Ren,Tianyi Xie,Zhongyuan Gu,Shifeng Deng,Xiaogang Yao,Huixing Lin
A “self-permeation” method was used to fabricate a Ca 0.9 La 0.067 TiO 3 -0.01Al 2 O 3 (CLT)-reinforced polysilylaryl-enyne/fiber multilayer board with different volume fractions of CLT (0–40 vol%). The microstructure, dielectric, mechanical, and thermal properties were fully studied. The results showed that the composite with optimal dielectric properties (ε r ∼8.75, tanδ∼0.0043) could be obtained when the volume fraction of CLT reached 30 vol%. Meanwhile, the thermal conductivity reached a high level of 0.644 W/(m·K) and 0.762 W/(m·K) at Z and X/Y directions, respectively. Due to the high decomposition temperature of PSAE, T d5 (the temperature corresponding to 5% weight loss) of composite loading with 30 vol% CLT was higher than 900℃, which indicates an excellent thermal resistance. And the bending strength could reach 115.3 MPa indicating excellent mechanical property. The novel polysilylaryl-enyne/fiber/Ca 0.9 La 0.067 TiO 3 -0.01Al 2 O 3 multilayer board with excellent performance is expected to be a candidate material for print circuit boards and widely used in the microwave communication field.
Y 2.5- x Bi 0.5 Al x Fe 5 O 12 (YIG-Al x ) ceramics have been synthesized at 1175 ℃ by the solid-state reaction method. The effects of the co-doped Bi 3+ , Al 3+ ions on the phases, micromorphology, and dielectric and magnetic properties of the yttrium iron garnets (YIG) were investigated. Excessive introduction of Al 3+ ions led to the collapse of the YIG lattice and precipitation of the Bi 3+ and Fe 3+ ions; while moderate Al 3+ doping improved the dielectric properties , but not the saturation magnetization. The YIG-Al 0.2 ceramics proved to have particularly good electromagnetic properties ( ε r = 18.34 ± 0.05@11.19 GHz, tan δ = 3.09 ± 0.55 × 10 −4 , M s = 19.82 ± 0.55 emu/g). Additionally, tightly bonded Y 2.3 Bi 0.5 Al 0.2 Fe 5 O 12 /Ni 0.8 Zn 0.2 Fe 2 O 4 (YIG-Al 0.2 /NZF) composite substrates were prepared by co-firing at 1175 ℃. The composite substrates exhibited superior electromagnetic properties (YIG-Al 0.2 : ε r = 18.37 ± 0.05@11.15 GHz, tan δ = 3.08 ± 0.55 × 10 −4 , M s = 21.09 ± 0.55 emu/g; NZF: M s = 67.5 ± 0.55 emu/g), which were slightly affected by the diffusion of Ni and Zn from the NZF. Our findings show that YIG-Al 0.2 /NZF substrates have great potential for use as RF band circulators.
危险品化学品经营许可证（带存储）